The entry \(l_{ij}\)  of \(L\)  is the limit of half-bound state \(\psi ^{(j)}\)  as \(x\)  goes to infinity along the edge \(e_i\) .
Let \(L^+\)  denote the Moore–Penrose pseudoinverse of \(L\) . Note that \(L^+\)  is a matrix of size \(r\times n\)  and it always exists [1]}. Since \(\ell \)  is an injection, the matrix \(L\)  has linearly independent columns and its pseudoinverse can be compute as
\(L^+=(L^*L)^{-1}L^*,\) 
